U.S. patent application number 12/744618 was filed with the patent office on 2010-10-07 for apparatus for unscrambling and aligning preforms.
This patent application is currently assigned to LA SEDA DE BARCELONA S.A.. Invention is credited to Paul Brown.
Application Number | 20100255142 12/744618 |
Document ID | / |
Family ID | 39345201 |
Filed Date | 2010-10-07 |
United States Patent
Application |
20100255142 |
Kind Code |
A1 |
Brown; Paul |
October 7, 2010 |
APPARATUS FOR UNSCRAMBLING AND ALIGNING PREFORMS
Abstract
The apparatus for unscrambling and aligning preforms comprises
two substantially parallel alignment rollers (121) and rotary
pushing means (122) mounted above the said alignment rollers for
pushing back incorrectly oriented preforms or nested preforms, and
is characterized by at least one of the following characteristics
(i) or (ii): (i) it comprises stopping means (30, 31) mounted above
the alignment rollers (121) for stopping correctly oriented nested
preforms (P2/P3) or an incorrectly oriented preform or incorrectly
oriented nested preforms (P4/P5) underneath the rotary pushing
means (122) until the rotary pushing means push back the stopped
preform(s), said stopping means (30, 31) being adapted for letting
a correctly oriented preform slide onto the alignment rollers, (ii)
it comprises guiding means (34) for lifting an incorrectly oriented
preform or incorrectly oriented nested preforms (P4/P5) into
contact with the rotary pushing means (122) said guiding means (34)
being adapted for letting a correctly oriented preform slide onto
the alignment rollers.
Inventors: |
Brown; Paul; (Wrexham,
GB) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
LA SEDA DE BARCELONA S.A.
El prat de Llobregat, Barcelona
ES
|
Family ID: |
39345201 |
Appl. No.: |
12/744618 |
Filed: |
August 1, 2008 |
PCT Filed: |
August 1, 2008 |
PCT NO: |
PCT/EP08/06369 |
371 Date: |
May 25, 2010 |
Current U.S.
Class: |
425/534 ;
198/389 |
Current CPC
Class: |
B29C 49/4205 20130101;
B29C 2049/4231 20130101; B65G 47/256 20130101; B65G 11/166
20130101; B29C 49/06 20130101 |
Class at
Publication: |
425/534 ;
198/389 |
International
Class: |
B65G 47/256 20060101
B65G047/256; B29C 49/42 20060101 B29C049/42; B65G 47/24 20060101
B65G047/24 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 27, 2007 |
EP |
07022926.5 |
Claims
1. An apparatus for unscrambling and aligning preforms, said
apparatus comprising two substantially parallel alignment rollers
and rotary pushing means mounted above the said alignment rollers
for pushing back incorrectly oriented preforms or nested preforms,
said apparatus comprising at least one of the following
characteristics: (i) stopping means mounted above the alignment
rollers for stopping correctly oriented nested preforms or an
incorrectly oriented preform or incorrectly oriented nested
preforms underneath the rotary pushing means until the rotary
pushing means push back the stopped preform(s), said stopping means
being adapted for letting a correctly oriented preform slide onto
the alignment rollers; (ii) guiding means for lifting an
incorrectly oriented preform or incorrectly oriented nested
preforms into contact with the rotary pushing means said guiding
means being adapted for letting a correctly oriented preform slide
onto the alignment rollers.
2. The apparatus of claim 1, comprising both characteristics (i)
and (ii) and wherein the guiding means are positioned upstream from
the stopping means.
3. The apparatus of claim 2, wherein the guiding means extend
downwards to the stopping means.
4. The apparatus of claim 1, wherein the guiding means are
constituted by two parallel sidewalls.
5. The apparatus of claim 4, wherein the said sidewalls are
separated by a distance that is less than the diameter of the neck
support ring of a preform.
6. The apparatus of claim 4, wherein the front edges of the
sidewalls are designed to facilitate the lifting of preform(s) onto
the upper edges of the sidewalls.
7. The apparatus of claim 6, wherein the front edges of the
sidewalls are inclined with reference to a plane that is
perpendicular to the axis of rotation of the rollers at a front
angle .alpha. of value greater than 0.degree..
8. The apparatus of claim 7, wherein the front angle .alpha. is
around 10.degree..
9. The apparatus of claim 4, wherein the lower edges of the
sidewalls are bevelled at their upstream end in order to facilitate
the entrance of the neck support ring of a correctly oriented
preform between said lower edges and the rollers.
10. The apparatus of claim 2, wherein the stopping means and the
guiding means are constituted by a guide comprising two main
sidewalls of height, that are joined together by an upper wall, and
comprising two sidewalls of smaller height that are an extension of
said main sidewalls.
11. The apparatus of claim 1, wherein the rotary pushing means are
constituted by a bladed wheel.
12. A feed system for feeding aligned and correctly oriented
preforms to a downstream machine, and comprising a bin for storing
preforms in bulk, a feed-elevator for removing the preforms from
the bin and for lifting up the preforms and dropping the preforms
at a pre-established rate into an apparatus according to claim
1.
13. Use of an apparatus of claim 1 for feeding aligned and
correctly oriented preforms to a downstream machine.
14. The use of claim 13, wherein the downstream machine is a
blow-moulding machine.
15. A system for manufacturing blow-moulded plastic containers, and
comprising a blow-moulding machine and an apparatus of claim 1 for
feeding the blow-moulding machine with aligned and correctly
oriented preforms.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an improved apparatus for
unscrambling and aligning preforms. This apparatus is used, for
example, for feeding preforms to a machine, like a blow-moulding
machine for making plastic containers.
PRIOR ART
[0002] In the field of plastic packaging, a well-known technique
widely used for manufacturing plastic containers is the two stages
injection and blow-moulding technique. In a first stage, plastic
preforms are moulded by injection in an injection machine. A
preform has a substantially tubular body that is closed at one
bottom end and is opened at the other upper end. A preform also
comprises a neck support ring in its upper part, close to its
opened mouth. In a second stage, the preforms are fed to a
blow-moulding machine that is used for making bi-axially oriented
containers by stretching and blowing each preform in a mould.
[0003] In this two stages injection and blow-moulding technique,
the injection machine for manufacturing the preforms and the
blowing-moulding machine for manufacturing the containers from the
preforms are two independent machines. In such case, a feeding
system of the type illustrated in FIG. 1 is used generally for
feeding the blowing-moulding machine with aligned and correctly
oriented preforms. More generally, such a feeding system can be
used for feeding any machine with aligned and correctly oriented
preforms.
[0004] More particularly, such a feeding system comprises an
apparatus for unscrambling and aligning the preforms, and generally
referred as "unscrambler". An unscrambler generally comprises two
rotary alignment rollers which are inclined to the horizontal and
which are substantially parallel to each other. These two rollers
are separated from each others in such a way to leave a space along
and between the rollers for the body of the preforms. The distance
between the two rollers is however sufficiently small for enabling
the two rollers to retain the preforms by their neck support
ring.
[0005] In operation, the preforms fall under the effect of gravity
onto the alignment rollers which are driven in rotation in opposite
directions. Under the combined effect of gravity and rotation of
the alignment rollers, the preforms tend to move and to be oriented
between the rollers in an upright position. Correctly oriented
preforms are thus aligned and supported on the two rollers by their
neck support ring, while the body of the preforms hangs down
between the rollers. The aligned and correctly oriented preforms
slide under the effect of gravity along the inclined alignment
rollers down to a downstream machine, and for example a
blow-moulding machine.
[0006] In order to improve orientation and positioning of the
preforms between the alignment rollers, unscramblers of the prior
art further comprise a rotary bladed wheel which is mounted above
the two alignment rollers. The axis of rotation of this bladed
wheel is transverse, more preferably substantially perpendicular,
to the axis of rotation of the rollers. In operation, the bladed
wheel is driven in rotation at a pre-established speed in such a
way that the blades of the wheel sweep the space above the rollers
and push back preforms that are not correctly oriented and
positioned between the two rollers, and also nested preforms that
can be correctly oriented and supported by the roller by the neck
support ring of the lower preform. The principle of this rotary
bladed wheel is that statistically the preforms become in theory
correctly oriented and positioned after a certain number of
pushes.
[0007] In practise, the usual unscramblers with rotary bladed wheel
often malfunction. Actually, in operation some preforms (a preform
alone or nested preforms) that are not correctly oriented are not
pushed back by the wheel, then slide beyond the bladed wheel and
are never correctly oriented on the alignment rollers. Such
incorrectly oriented preforms (preforms alone or nested preforms)
cause a jam at the output of the unscramblers. It happens also that
nested preforms that are correctly oriented on the alignment
rollers are not pushed back by the wheel and slide beyond the
bladed wheel. Such correctly oriented but nested preforms also
cause a jam at the output of the unscramblers. These jams may lead
to a stoppage of the feed of preforms at the input of the
downstream machine (for example a blow-moulding machine) and may
cause a prejudicial shutdown of this machine. When a jam occurs, a
fastidious manual intervention is required for removing the jammed
preform(s).
OBJECTIVE OF THE INVENTION
[0008] The objective of the invention is to propose a simple and
efficient solution to increase the reliability of aforesaid
unscramblers of the prior art and to decrease the number of preform
jams downstream from such unscramblers.
SUMMARY OF THE INVENTION
[0009] This objective is achieved by the apparatus for unscrambling
and aligning preforms as defined in claim 1.
[0010] This apparatus of the invention is characterized by at least
one of the following characteristics (i) or (ii): [0011] (i) it
comprises stopping means mounted above the alignment rollers for
stopping correctly oriented nested preforms or an incorrectly
oriented preform or incorrectly oriented nested preforms underneath
the rotary pushing means until the rotary pushing means push back
the stopped preform(s), said stopping means being adapted for
letting a correctly oriented preform slide onto the alignment
rollers, [0012] (ii) it comprises guiding means for lifting an
incorrectly oriented preform or incorrectly oriented nested
preforms into contact with the rotary pushing means, said guiding
means being adapted for letting a correctly oriented preform slide
onto the alignment rollers.
[0013] By the wording "correctly oriented preform", it is meant
therein that the preform is supported and suspended in its upright
position onto the alignment rollers by its neck support ring. The
wording "incorrectly oriented preform" used therein means any other
orientation of a preform, wherein the preform does not fulfil the
above definition of "correctly oriented preform". By the wording
"correctly oriented nested preforms", it is meant therein that the
preforms are nested and are supported and suspended in their
upright position onto the alignment rollers by the neck support
ring of the lower preform. The wording "incorrectly oriented nested
preforms" used therein means any other orientation of nested
preforms that does not fulfil the above definition of "correctly
oriented nested preforms".
[0014] In one variant, only the said characteristic (i) can be
implemented. In another variant, only the said characteristic (ii)
can be implemented. In another variant, both characteristics (i)
and (ii) can be implemented.
[0015] When both characteristics (i) and (ii) are implemented, the
guiding means are preferably positioned upstream from the stopping
means, and more particularly extend downwards to the said stopping
means.
[0016] Other optional technical characteristics of the apparatus of
the invention are defined in the appended claims.
[0017] A further object of the invention is a feed system for
feeding aligned and correctly oriented preforms to a downstream
machine, said feed system comprising a bin for storing preforms in
bulk, a feed-elevator for removing the preforms from the bin and
for lifting up the preforms and dropping the preforms at a
pre-established rate into an aforesaid apparatus of the invention
for unscrambling and aligning preforms.
[0018] A further object of the invention is the use of the
aforesaid apparatus of the invention for feeding aligned and
correctly oriented preforms to a downstream machine, more
especially a blow-moulding machine.
[0019] A further object of the invention is a system for
manufacturing blow-moulded plastic containers, and comprising a
blow-moulding machine and an apparatus of the invention for feeding
the blow-moulding machine with aligned and correctly oriented
preforms.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The characteristics and advantages of the invention will
appear more clearly on reading the following detailed description
which is made by way of non-exhaustive and non-limiting example,
and with reference to the appended drawings, as follows:
[0021] FIG. 1 is a diagrammatic view of a feed system of the prior
art which comprises an unscrambler with alignment rollers and
rotary bladed wheel, and which is used for feeding a downstream
machine with aligned and correctly oriented preforms,
[0022] FIG. 2 is a side view of a novel guide of the invention,
[0023] FIG. 3 is an end view of the guide of FIG. 2, with a
correctly oriented preform,
[0024] FIG. 4 is a diagrammatic side view of the guide of FIG. 2
mounted above the alignment rollers and underneath the rotary
bladed wheel of an unscrambler, and showing the stop by the guide
of correctly oriented nested preforms,
[0025] FIG. 5 is a end view of the assembly of FIG. 4,
[0026] FIG. 6 and FIG. 7 are others diagrammatic side views that
are similar to FIG. 4, but that show two other examples of stop of
incorrectly oriented nested preforms.
DETAILED DESCRIPTION
[0027] Referring to FIG. 1, a usual feeding system 1 is used for
feeding preforms P to a downstream machine 2, for example a
blow-moulding machine. The feeding system 1 comprises a bin 10
wherein the preforms P are dumped in bulk, and a feed-elevator 11
for removing the preforms from the bin 10 and for lifting up the
preforms and dropping the preforms P at a pre-established rate into
the upper part of an apparatus 12 for unscrambling and aligning the
preforms.
[0028] This apparatus 12 comprises a trough 120 and two rotary
alignment rollers 121 which are mounted inside the trough 120. The
axis of rotation 121a of each roller 121 is inclined to the
horizontal. Referring to FIG. 5, the rollers 121 are substantially
parallel to each other, and are separated from each other in such a
way to leave a space along and between the rollers for the body B
of the preforms P. The distance between the two rollers 121 is
however sufficiently small for enabling the two rollers to retain a
preform P in its upright position by its neck support ring C.
[0029] In operation, the two rollers are driven in rotation in two
opposite directions (FIG. 5/arrows F). Under the effect of gravity,
the preforms P fall in the trough 120 onto the alignment rollers
121. Under the combined effects of gravity and rotation of the
alignment rollers 121, the preforms P tend to move and to be
oriented between the rollers 121 in an upright position (FIG. 5).
Correctly oriented preforms are thus aligned and supported on the
two rollers 121 by their neck support ring C, while the body B of
the preforms hangs down between the rollers 121. The aligned and
correctly oriented preforms P slide under the effect of gravity
along the inclined alignment rollers 121 down to a feed rail 13
which guides the preforms down to the entry of the downstream
machine 2. In this feed rail 13, the preforms P gather in a
continuous line at the entry of the downstream machine 2.
[0030] The sliding direction of the preforms onto the rollers 121
through the unscrambling and aligning apparatus 12 is identified by
arrow A on the figures. The words "upstream" and "downstream" used
therein are defined in reference to this sliding direction A.
[0031] The apparatus 12 further comprises rotary pushing means 122
which are mounted above the two rotary rollers 121. These rotary
pushing means 122 are used for pushing back preforms that are not
correctly oriented and positioned between the two rollers 121 (like
preforms P' on FIG. 1), and also nested preforms that can be
correctly oriented and supported by the rollers 21 by the neck
support ring C of the lower nested preform.
[0032] In the particular variant of FIG. 1, theses rotary pushing
means 122 are constituted by a rotary wheel comprising a rotary
shaft 122a fitted with blades 122b. The axis of rotation of the
shaft 122a is substantially perpendicular to the axis of rotation
121a of the rollers 121. In operation, the shaft 122a is driven in
rotation at a pre-established speed in the direction identified by
arrow G on the figures. The blades 122b of the wheel sweep the
space above the rollers 121 and thus push back preforms that are
not correctly oriented or nested preforms.
[0033] In practise, such a bladed wheel 122, when used alone, is
however not reliable, and in operation some preforms that are not
correctly oriented or some nested preforms can slide down beyond
the bladed wheel 122 and provoke a prejudicial jam on the feed rail
13.
[0034] According to the invention, in order to increase the
reliability of the unscrambling and aligning apparatus 12, a novel
guide 3 is mounted above the rollers 121 and is used in combination
with the rotary pushing means 122.
[0035] FIGS. 2 and 3 show a particular structure for this guide 3,
which is now going to be described in details, but bearing in mind
that the invention is not limited however to this particular
structure.
[0036] In the variant of FIGS. 2 and 3, the guide 3 is constituted
by an inverted U-shaped profile, for example a stainless hot rolled
flat bar, comprising two main vertical sidewalls 30 joined together
by an upper wall 31. The two main vertical sidewalls 30 and the
upper wall 31 delimit an internal channel 32 of height H and width
W for the preform neck (FIG. 3). Threaded holes 31a are pierced
through the upper walls 31, and are used for fastening the guide 3
above the rollers 121 by means for example of screws 31b (see e.g.
FIG. 4).
[0037] At its upstream end, the guide 3 comprises an upper L-shaped
cut 33. In the region of this cut 33, the guide 3 has no upper
wall, but has only upstream sidewalls 34 of smaller height h which
are an extension of the main sidewalls 30. Referring to FIG. 3, the
distance W (i.e. width of channel 32) between the sidewalls 30 (or
between the upstream sidewalls 34 of smaller height h) is
preferably smaller than the diameter D of the neck support ring C
of a preform P.
[0038] Referring to FIGS. 4 and 5, the guide 3 is mounted above and
inbetween the two rollers 121. The lower edges 35 of the sidewalls
30 and 34 are parallel to the axis 121a of the rollers 121 and are
close to the surface of the rollers 121. The distance between these
lower edges 35 and the surface of the rollers 121 is sufficient for
allowing the neck support ring C of a preform P, which is correctly
oriented and suspended on the rollers 121 in its upright position,
to slide between the lower edges 35 and the surface of the rollers
121.
[0039] In the particular variant of FIG. 2, the lower edges 35 of
the sidewalls 34 are bevelled at their upstream end 35a [FIG.
2/angle .beta.] in order to facilitate the entrance of the neck
support ring C of a correctly oriented preform (P1) between said
lower edges 35 and the rollers 121.
[0040] In reference to FIGS. 4, 6 and 7, the guide 3 is fastened
with regard to the bladed wheel 122 in such way that the upstream
front edge 31c of the upper wall 31 is positioned underneath the
bladed wheel 122, more particularly at a position downstream from
the axis of rotation 122c of the bladed wheel 122. Furthermore, the
upstream front edges 34a of the two sidewalls 34 of smaller height
h are positioned underneath the bladed wheel 122, in particular
upstream from the axis of rotation 122c of the bladed wheel 122.
The upper wall 31 does not stop the rotation of blades 122b, and
the height h of the sidewalls 34 is also sufficiently small for
allowing the rotation of the blades 122.
[0041] In reference to FIG. 4, when a correctly oriented preform is
supported in its upright position between the two rollers 121, like
for example the preform referenced P1, the guide 3 does not stop
this correctly oriented preform P1, and said correctly oriented
preform P1 slides downwardly between the rollers 121 and the guide
3 beyond the rotary bladed wheel 122. When nested preforms P2/P3,
with the lower preform P2 that is correctly oriented, manage to
slide underneath the bladed wheel 122, such nested preforms P2/P3
are necessarily temporarily stopped underneath the bladed wheel 122
by the upstream front edge 31c of the guide 3, until the next blade
122b pushes back the nested preforms P2/P3 for recycling (in the
direction opposite to arrow A). Under the impact of the blade, the
nested preforms P2/P3 are also very often denested.
[0042] In reference to FIG. 6 or FIG. 7, when incorrectly oriented
nested preforms P4/P5 slide onto the rollers 121 down to the guide
3, they are firstly temporarily stopped by the front edges 34a of
the two sidewalls 34 of smaller height h. Advantageously, when the
distance W between the sidewalls 34 is smaller than the diameter D
of the neck support ring C of the preforms, even in the particular
case where the longitudinal axis of the nested preforms is parallel
to the axis of the rollers 121, the neck support ring C of one of
the nested preforms is necessarily stopped by the front edges 34a
of the two sidewalls 34 (as shown on FIGS. 6 and 7).
[0043] Then under pressure of the other preforms that are
continuously fed behind, the stopped nested preforms P4/P5 are most
often lifted up onto the upper edges 34b of the sidewall 34, and
are thus brought upwardly into contact with the rotary blades 122b
of the wheel 122, and pushed back for recycling by the bladed wheel
122.
[0044] Once the nested preforms P4/P5 are positioned onto the upper
edges 34 of the sidewalls 34, they are stopped vertically by the
upper edges 34a and are thus necessarily maintained at level that
is sufficiently close to the rotary blade 122b for obtaining a
reliable push back of the preforms by the blades.
[0045] Furthermore, once the nested preforms P4/P5 are positioned
onto the upper edges 34b of the sidewalls 34, they can not slide
down beyond the wheel 122 because they are stopped at least by the
upstream front edge 31c of the upper wall 31.
[0046] In some cases, it may also happen that under the pressure of
the preforms that are continuously fed behind, nested preforms
P4/P5 that have been stopped by the front edges 34a are displaced
in such a way that the lower preform P4 becomes correctly oriented
and positioned between rollers 121. In that case, the correctly
oriented nested preforms P4/P5 can pass trough the sidewalls 34,
with the neck support ring C of the lower preform P4 being guided
between the lower edges 35 of the sidewalls 34 and the rollers 121.
In such a case, if the nested preforms P4/P5 reach the upper wall
31 of the guide 3, they are necessarily stopped by the front edge
31c of said upper wall 31 (same case than for nested preforms P2/P3
on FIG. 4).
[0047] If an incorrectly oriented preform alone slides on the
rollers 121 down to the guide 3, it is also firstly stopped by the
front edges 34a of the two sidewalls 34 of smaller height h, and
then most often lifted up onto the upper edges 34b of the sidewalls
34 and brought upwardly into contact with the blades 122b of the
wheel, and then necessarily pushed back for recycling by the bladed
wheel 122. In some cases, it may also happen that under pressure of
the preforms that are continuously fed behind, an incorrectly
oriented preform that has been stopped by the front edges 34a is
displaced in such a way that it becomes correctly oriented and
positioned between rollers 21, without being lifted up onto the
upper edges 34b of the sidewalls 34. In such a case, this correctly
oriented preform slides down through the guide 3 underneath the
lower edge 35 of the guide 3 without being stopped by the front
edge 31c (like preform P1 on FIG. 4, 6 or 7), and without coming
into contact with the bladed wheel 122.
[0048] Preferably, the front edges 34a of the sidewalls 34 are
designed in order to facilitate the lifting of a preform or nested
preforms onto the upper edges 34b under the pressure of the other
preforms continuously fed behind. In particular, in reference to
FIG. 6, the front edges 34a of the sidewalls 34 are inclined with
reference to a plane E that is perpendicular to the axis of
rotation 121a of the rollers 121 at a front angle .alpha. of value
greater than 0.degree.. A suitable value for this front angle
.alpha. is for example around 10.degree..
[0049] The invention is not limited to the use of a guide 3 having
the particular structure that has been described in reference to
the appended drawings, but the scope of protection encompasses any
apparatus having the characteristics defined in the claims. In
particular, the guide 3 is not necessarily made of one piece, but
can be constituted by a monolithic assembly. In another variant of
the invention, the guide 3 could be made of two separated elements:
upstream guiding means 34 for lifting up incorrectly oriented
preforms or incorrectly oriented nested preforms and separated
downstream stopping means 30, 31. In another variant, the
downstream stopping means could be made only of one stop like the
upper wall 31 (i.e. without the sidewalls 30). In another variant
of the invention, the guide 3 could be only constituted by the
sidewalls 30 and upper wall 31 (i.e. without the sidewalls 34 of
smaller height) or could be only constituted by the sidewalls 34 of
smaller height h (i.e. without the use of stopping means 30, 31
downstream from the axis of rotation of the rotary pushing means
122). On the drawings, the front edges 34a of the sidewalls 34 are
positioned underneath the rotary pushing means 122. In another
variant, theses front edges 34a could be also positioned upstream
from the rotary pushing means 122.
* * * * *